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Reduction of hexavalent chromium with scrap iron in a fixed bed reactor

Reduction of hexavalent chromium with scrap iron in a fixed bed reactor Abstract The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time (EBCT), and initial Cr(VI) concentration on Cr(VI) reduction were studied. The results showed that the pH, EBCT, and initial Cr(VI) concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57 mg Cr(VI)·g−1 Fe0 at pH 3, 5, and 7 (initial Cr(VI) concentration 4 mg·L−1, EBCT 2 min, and temperature 25°C), 0.51, 1.51, and 2.85 mg Cr(VI)·g−1 Fe0 at EBCTs of 0.5, 2.0, and 6.0 min (initial Cr(VI) concentration 4mg·L−1, pH 5, and temperature 25°C), and 2.99, 1.51, and 1.01 mg Cr(VI)·g−1 Fe0 at influent concentrations of 1, 4, and 8 mg·L−1 (EBCT 2 min, pH 5, and temperature 25°C), respectively. Fe(total) concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr(VI) ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr6 +·g−1 Fe. Scanning electron microscope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png "Frontiers of Environmental Science & Engineering" Springer Journals

Reduction of hexavalent chromium with scrap iron in a fixed bed reactor

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References (49)

Publisher
Springer Journals
Copyright
2012 Higher Education Press and Springer-Verlag Berlin Heidelberg
ISSN
2095-2201
eISSN
1673-7520
DOI
10.1007/s11783-012-0413-z
Publisher site
See Article on Publisher Site

Abstract

Abstract The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time (EBCT), and initial Cr(VI) concentration on Cr(VI) reduction were studied. The results showed that the pH, EBCT, and initial Cr(VI) concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57 mg Cr(VI)·g−1 Fe0 at pH 3, 5, and 7 (initial Cr(VI) concentration 4 mg·L−1, EBCT 2 min, and temperature 25°C), 0.51, 1.51, and 2.85 mg Cr(VI)·g−1 Fe0 at EBCTs of 0.5, 2.0, and 6.0 min (initial Cr(VI) concentration 4mg·L−1, pH 5, and temperature 25°C), and 2.99, 1.51, and 1.01 mg Cr(VI)·g−1 Fe0 at influent concentrations of 1, 4, and 8 mg·L−1 (EBCT 2 min, pH 5, and temperature 25°C), respectively. Fe(total) concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr(VI) ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr6 +·g−1 Fe. Scanning electron microscope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron.

Journal

"Frontiers of Environmental Science & Engineering" – Springer Journals

Published: Dec 1, 2012

Keywords: Environment, general

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